1990 Temp Gauge not working?

[Erikinho]

Options for repair? I've found some videos on YT and there are two sensors I need to check one on top and one below next to the oil filter...

 

[Uncle Gump]

I moved your post to the gauges forum.

What engine?

There are two coolant monitoring devices. A single wire sender for the gauge and a two wire sensor for coolant temp info to the ECM.

 

[RonD]

If its a 2.3L 4cyl, then its the single wire SENDER near the oil pressure SENDER and oil filter

Drawing here: https://i0.wp.com/i.postimg.cc/h43ZDb31/imageedit-0-8830182944.png?w=2000&ssl=1

Dash gauges use 12volt SENDERS, just FYI
Engine computers use 5volt Sensors, always 2 wires or more on a Sensor

 

[Erikinho]

If its a 2.3L 4cyl, then its the single wire SENDER near the oil pressure SENDER and oil filter

Drawing here: https://i0.wp.com/i.postimg.cc/h43ZDb31/imageedit-0-8830182944.png?w=2000&ssl=1

Dash gauges use 12volt SENDERS, just FYI
Engine computers use 5volt Sensors, always 2 wires or more on a Sensor

So, I should be able to go underneath the car and unscrew the old one and put the new one in, easy..? But, I have to switch it quickly as fluid is coming out right...? And there is no fuse associated with the gauge itself right? Thanks!

 

[RonD]

No, you will need to drain some coolant out first, so its below the level of the Sender
There is no way to pull out the old and put in the new without making a BIG MESS, lol


But I would first test if its the Sender that is the issue
Get a jumper wire and connect it to a ground, like Battery Negative
Pull off the one wire at the Sender and hook it to the Grounded jumper wire
Get in the cab and turn on the key
The temp gauge should go all the way up to HOT, if so wire, gauge(and fuse) are all OK, replace Sender

If gauge doesn't move then the issue is with the wire or gauge, the "fuse" powers the other gauges so unless all the gauges are dead its not a fuse issue

Sender needs to have Bare Metal Threads at the bottom, so it can Ground to the Engine, so don't use tape or sealant on the lower threads

 

[Erikinho]

No, you will need to drain some coolant out first, so its below the level of the Sender
There is no way to pull out the old and put in the new without making a BIG MESS, lol


But I would first test if its the Sender that is the issue
Get a jumper wire and connect it to a ground, like Battery Negative
Pull off the one wire at the Sender and hook it to the Grounded jumper wire
Get in the cab and turn on the key
The temp gauge should go all the way up to HOT, if so wire, gauge(and fuse) are all OK, replace Sender

If gauge doesn't move then the issue is with the wire or gauge, the "fuse" powers the other gauges so unless all the gauges are dead its not a fuse issue

Sender needs to have Bare Metal Threads at the bottom, so it can Ground to the Engine, so don't use tape or sealant on the lower threads

Thanks Ron for your advice and direction! I couldn't locate the fuse location on the chart...? Where is the fuse located? Thanks! Oh!, and where would be the best place to obtain a new sender? Autozone, NAPA... I'm in San Diego. Thanks!

 

[RonD]

1990 should be same as 1991

Fuse 17 powers gauges

Any autoparts store will have that Sender, Ford used the same one for years and years on ALL engines
If possible take a picture of yours and its ONE WIRE connector
Then open the box and compare, about the only thing that changed was the connector for the one wire

You DO NOT want an ECT sensor, which is what they will usually try to sell you, lol, it has 2 wire connector

 

[Erikinho]

Hi Ron, So this is the part I believe I will be getting, correct? https://www.napaonline.com/en/p/MPETS6628SB?impressionRank=1
And the motor is the 2.9L... Also, the connector: https://www.napaonline.com/en/p/ECHEC104?impressionRank=3
Besides this sensor does the temp gauge read any temps from other sensors on the motor or only this one?
Thanks!

 

[RonD]

Gauge only has the one Temp SENDER, it is not a "sensor", just a small difference in words but matters in this instance

An engine computer, for fuel injection, has its own temp SENSOR, no connection to gauge, this is why the word description matters in this case
Sensors are 5 volt, always 2 wire
Senders are 12volt, can be 1 wire or 2 wire

NAPA calls it a "sensor" but its actually a Sender that is pictured

 

[Erikinho]

Hi Ron,
So, is this sensor connected to the temp gauge? https://www.napaonline.com/en/p/DEMTS10001?impressionRank=2

 

[RonD]

No, that would be for the Computer not a gauge

Previous one was for gauge: https://www.napaonline.com/en/p/MPETS6628SB?impressionRank=1

 

[Erikinho]

Perfect! Thank You very much!!!

 

[Erikinho]

By the way, I've heard about engine swaps..? A neighbor has a 1985 ranger. I was wondering if there's a post here about swapping out the motor for a V6..?

 

[RonD]

Easy engine swaps ended with fuel injection unless you are swapping in the same engine model

In a 1985 Ranger best choice would be a 302 V8 swap, carb and distributor, no computer, in my opinion
Need to swap transmission as well, anytime you change engine model, so V6 or V8 would require different transmission, V8 just makes more sense, labor and cost is the same, and you have a Ranger Ford never made, V8 Ranger

302/5.0l OHV engine is narrow, 18" wide, so fits in Ranger engine bay

 

[Erikinho]

Great! Sounds fun! Will look into it! Be well!